ABC supermarket orders flour bags that are measured in units. The daily demand is constant and deterministic at $100$ units. However, the lead time varies, but assumed to have followed normal distribution with an average of $10$ days, and a standard deviation of $2$ days. ABC wishes to maintain a $90\%$ service level. What should be the safety stock? Round$-$up to the nearest integer

$329$

$300$

$256$

$330$

$237$

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